Precision tool adjustment device



1956 L. G. ARPIN PRECISION TOOL ADJUSTMENT DEVICE Filed No 25, 1952 IN VEN TOR.

A MFZL ATTORN E Y United States Patent PRECIS ON TOOL, ADJU TMENT DEVICELeon. G; All-'Pill, Montclair, N; J. Applica ion November 25,, 1952,,Serial No. 322,523.

1 Claim. ((31,182-24) This invention relates to'a precision tooladjustment de ic n. ne r. machines su h. as lathes, milling mahines andsimilanm hani'sms. This applicati n is acoutiiiuati n. in part of myPrior appl ati n: S rial No. 283,116, filedAprilZZJ. ,952.

In said prior application, as well' asiin application Serial No.296,981, filedthereaftenl disclosed means for making positive, preciseadjustments of a cutting tool where. only close'tolerances are permittedin the finished product and where precise dimensions were accordinglyrequired. The invention was illustrated in connection with alathewherein the cu t ng l' or the like must. e adjpsted with precision inorder to produce an accurate machining of, the work.

The device of the instant-invention is likewise illustrated asapplied'to alathe and specifically, means are illi strated, to P e pr onmovemen of: th ool holder apart r m th n m l. t ng, iae a.n jsrnv thereor. As is well understood; the tool holder is fixed in a compound whichcomprises a slidable head operating in a, clove tail groove o s t t ng,h ompound. slid ways. Mov ment ofthe slidabl'e' head; is controlled by alead Screw of a given pitch. The lead screw is disposed, within'an internally threaded nut and rotation of the screw produces movement of thesli'dable compound head. The com pound' feedv screw moves, transversely,the ihternally threadednut withwhich it eo.-act s beingfixed'.

In my" prior applications I disclosed systems whereby the; lead screwcould be actuated either its convene ti'onal' ball and crank handleorinde e dentlylthereof by, a worm gear mechanism; The worm gear mechanismdthenrecisionadjustment...

While my prior systemshave functioned effectively in producing the;desired result, I have devised what I now con i er a. s perior systemin. that: I: have by rassedi or elimi ated. movemem. of. he, l adcompletely while aw r he essa hie ne pre ision. m wfimfint of thecommundheath.

The elimination of lead. screw. movement for producing adjustment hasbrought about unusuallydesirable results, themost important being thecontinued accuracy of the adjustment mechanism. over long periods oftime notwithstanding any wear to which the lead screw is subjected.

Thus, even should the teeth of the lead screw or the threads of itsco-acting nut develop considerable backlash, it will have no effect uponthe precision adjustment of the disclosed mechanism. The mechanism isfurther of pronounced simplicity as regards production and installationand a minimum of changes are required in conventional lathe equipment.

The invention is realized by employing a specially constructed two piececollar device on the lead screw shaft and disposed forwardly of thecompound head. This collar device is made adjustable in such a way thatit operates directly on the compound head so as to slide it along thecompound slideways independently of the lead screw os its co-acting nut,a result, it is believed, which has been considered virtuallyimpossible.

Patented Jan. 3, 1956 2 --T,he, invention Will-be further-understoodfromthe fol.- lowing description and, drawings in which:

Figure Lisatop plan view partly broken away, of, a lathe showingthe workholding. and cutting means. and provided with, the device of the instantinvention;

V Figure 2; is, an enlarged cross-sectional view takensubstantially.along th e lines of. Figure 1;

Figure ,3 is an. enlarged, top. plan view of the adjustable collar; 7 t

Figure 4, is, across-sectional view as taken along the lines 4-4 ofFigure 2; and

Figure. 5, is a: cross sectional view as taken along the hues 5=-5 ofFigure}.

The invention is. shownv as applied. to a lathe in which 10 is. the bed,11 andv 12 the bedways, 13- the headstock and, 14 the tailstock.Headstock 1-3- isillustrated in carrying-the enter 15, while, tailstock14, carries a chuck 16, the, work being supported between the center 15and the chuck 16.

Slidably. arranged on the ways are the saddle members 11 and 1,8' whichbear the cross-slide 19 Disposed on the cross-slide is the compound 20which carriesthe-tool holden 21 which, in. turn carries the cutting tool22; The compound. is actuated bodily by the slide-1S1 by operat ingthe,bolt and. crank handle 23- while the compoundhead is actuated byoperating the handle 24'.

It will: be recognized that when handle 24 is rotated, employing theconventional indicia; wheel 24a as a refer $11C. means, the,compoundfeed screw or lead: screw: is actuated and. the compound head ismoved accordingly. In t esame an. when handle 23' s: ro t p yi the.conventionalindicia wheel 25 as. a, ref rence-m s. cross feed. screw orlead screw is actuated andv the compound ismoved bodily. V v

. The djusting de ice, at the in tant inventionis illu trated as beingconnected to the shaft. 26' of compound lead crew. 27.- Lea screw 21 is;employed in a convention l. 'launeli for making normal or roughadjustments. 'Ehus,, ii1ndle 2,4 is, rotated, for this; purpose, Whichin turn rotateslead. screw 2.7., Since, inthe compound'head, the.- cd-aelg t: 28.. is. fixed. in respect to the stationary. bas 28a, the leadscrew 2.7. necessarily travels transversely of the nutlS as itrotates.Duringi'such transverse movement, it, carries the compound head 29-with: it in conventjjonal manner, so as to. produce; the requiredtransverse adil stmeutof the comnoundiheads Aooordinglh. to the, presentinvention, L have. devised meimsfor actuating the compound head. 29independ ntly- 9 the, actuation of the lead screw 27 In. the form shown,this is accomplished by employing an adjustable collar device.comprising, the. threaded. collar. 30 and: the hii' 111 .31 isposedon.the shaft 26. of lead screw 27. ,blfe. 31 is, freely rotatable. on the,screwshaft and, is formed, with an externall readed, hub- 342v which isengaged by; the internal threads. of the central, opening or bore of Q lfdl 30 although the.- complementary threads ay, be otherwise. isp sedas. will. be. evident. Collar 30"is secured to the end. face ofcompound, head-29. by. bolts 33 as illustrated in Figure 5, While collar30 is disposed around the screw shaft it is free thereof and is notaffected by rotation of the screw.

Thimble 31 is formed with a bevelled flange 34 which embraces collar 30.Flange 34 bears indicia so that it ing instrument. As an example, it maythen be found that the adjustment of the tool holder is off .0005 inch.Ordinarily, slight inaccuracies such as this could be corrected byactuation of the lead screw only with very great difliculty, if at all.The reason, therefore, is that the thread of lead screw 27 is usuallypitch and the indicia wheel 24a bears 100 marks. Therefore, each markrepresents .001 advancement or retraction of the lead screw whichactually means a .002 change in diameter of the article being machined.It will be recognized therefore, that it is an extremely diflicult taskto accurately produce a .0005 change in diameter since it would berequired to visually divide each mark of wheel 24a into a fraction.

In accordance with the present invention, the thimble 31, which isprovided with a knurled outer surface, is manually rotated so as toadvance or retract the collar by the mating of its internal threads withthe threads of hub 32. If the collar 30 is advanced inwardly withinthimble 31, it draws the compound head correspondingly effects theadvancement of compound head 29. In effect,

the collar 30 and thimble 31 represent an expansible or contractablecollar device which is varied in its effective thickness and is furthercapable of precision adjustment in accordance with the pitch of themating threads. As an example, the hub 32 bears threads of pitch so thata complete turn of thimble 31 effects a movement of .025". Flange 34bears 50 marks so that each mark advances the compound head .0005.Furthermore, the wheel 31 being approximately 2 inches in diameter, theindicia wheel 34 is conveniently provided with half marks 38 so thatthese half marks permit the accurate advance or retraction of thecompound head .00025", a result which is virtually impossible ofaccomplishment in conventional mechanism.

It is desirable to insure against rotation of the lead screw duringadjustment by the eXpansible collar disclosed. Accordingly, I provide aset screw 39 which may be tightened by hand against the lead screw 27for preventing rotational movement thereof. On the other hand, when thecompound head 29 is actuated by my mechanism, the end of screw 39 willslide along the shaft 27. It will be recognized that the screw 39 neednot and should not be tightened down very securely since it is onlyintended to prevent accidental rotation of the lead screw 27. Set screw39 may be disposed in the conventional oil hole found in the compoundhead, such oil hole being threaded in order to receive the threadedscrew 39.

Means are also provided to insure against wear or backlash in thethreads of collar 30 and hub 32. Such means are shown in Figure 5 wherethe collar 30 is disclosed as formed with a split 40 which is traversedby a bolt 41. If, after some use, some wear should develop between thethreads, it is only necessary to tighten up on bolt 41 so as to reducethe extent of the split 40 and tighten the collar 30 around the hub 32.

It will be recognized that after normal or rough adjustment has beenmade by actuating handle 24, it may be necessary to retract the compoundhead through the improved mechanism. However, it may be found at thistime that the expansible collar device is at the limit of itscontraction. This would obviously prevent corresponding furtherretraction of the compound head. Accordingly, it is desirable to providethe periphery of collar 30 with indicia 42 so that the edge 43 of flange34 may be disposed at an intermediate or zero position 44 prior to thenormal or rough adjusting operation. In this way, ability to move thecompound head either way is assured. Indicia 44 may be simply set forthin zero and plus 50, minus 50 designations, the numeral 50 indicating amovement of .050". Indicia 44, it will be noted is arrangedperpendicularly relative to indicia of flange 34.

While I have described my invention as being applied to the compoundhead actuating mechanism, it is obvious that it may likewise be appliedto the cross feed mechanism for actuating the compound bodily. For thispurpose, the collar device is merely disposed forwardly of the indiciawheel 25 in place of the collar 50 in Figure 1.

What is claimed is:

In a lathe compound feed having a rotatable feed screw and shaft, and acompound which is adjusted by the rotation of said feed screw, meansindependent of the rotation of said feed screw for producing precisionadjustment of said compound, said means comprising an indicia wheelfreely rotatable on said feed screw shaft, an externally threaded hub onsaid wheel, the threads of said hub being of a higher pitch than thethreads of the feed screw, a collar having a central bore and disposedaround the feed screw shaft while being free thereof, said bore beingthreaded and mating with the wheel hub threads for retracting orattracting the collar, said collar being connected to the compoundwhereby said retraction or attraction of the collar produces acorresponding movement of the tool holder, and a hand operated screw onsaid compound, said screw being adapted to be tightened against saidfeed screw shaft for preventing rotation thereof during rotation of saidwheel, a flange bearing indicia markings for indicating the extent ofrotational action of said wheel, and additional indicia markings on saidcollar, said collar markings being perpendicularly arranged relative tothe wheel flange markings for indicating the extent of attraction orretraction of said collar within said flange.

References Cited in the file of this patent UNITED STATES PATENTS1,290,550 Hardinge Ian. 7, 1919 1,508,794 Ingham Sept. 16, 19242,619,863 Bechler Dec. 2, 1952 2,677,296 Morgan May 4, 1954 FOREIGNPATENTS 127,581 Germany Jan. 24, 1902 486,012 France Mar. 5, 1918

